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HURRICANE FLOYD DISCUSSION NUMBER 13
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT FRI SEP 10 1999
SATELLITE IMAGERY AND DATA FROM AN AIR FORCE RESERVE UNIT
RECONNAISSANCE AIRCRAFT THIS AFTERNOON INDICATE THAT FLOYD IS NOW
BECOMING BETTER ORGANIZED. AN EYE APPEARED BRIEFLY THIS
AFTERNOON...AND FOR THE FIRST TIME...THE FIX FROM THE AIRCRAFT
PLACED THE LOW-LEVEL CENTER IN THE MIDDLE OF THE DEEP CONVECTION AND
IN GOOD AGREEMENT WITH THE SATELLITE IMAGERY. ALTHOUGH THE WINDS
HAVE NOT INCREASED AT THIS TIME...THE MSLP REPORTED BY DROPSONDE WAS
977 MB...12 MB LOWER THAN 6 HOURS AGO. THE MOST RECENT PASS THROUGH
THE CENTER SUGGESTS THAT THE PRESSURE HAS DROPPED ANOTHER MB OR TWO.
IN MANY STORMS PRESSURE FALLS PRECEDE WIND INCREASES...AND WE EXPECT
THE WINDS TO CATCH UP TO THE IMPROVED STRUCTURE SOON. THE SHIPS
INTENSITY FORECAST MODEL BRINGS FLOYD TO CATEGORY THREE ON THE
SAFFIR-SIMPSON SCALE IN 72 HOURS AND THE OFFICIAL FORECAST CONCURS.
THE SHORT-TERM MOTION OF THE LOW-LEVEL CENTER HAS BEEN TO THE NORTH-
NORTHWEST...BUT THIS IS DUE LARGELY TO THE CHANGES IN STORM
STRUCTURE. A MORE REPRESENTATIVE MOTION IS 310/10. ALL THE
GUIDANCE IS IN GOOD AGREEMENT ON A NORTHWEST MOTION FOR THE NEXT DAY
OR SO...FOLLOWED BY A TURN TO THE WEST-NORTHWEST. THE AVN SHOWS THE
TROUGH IN THE EASTERN STATES LIFTING OUT...WITH STRONG RIDGING
DEVELOPING NORTH OF THE CYCLONE. THE OFFICIAL FORECAST IS SIMILAR
TO THE PRECEDING PACKAGE...ROUGHLY HALFWAY BETWEEN THE GFDL AND THE
UKMET.
FRANKLIN
FORECAST POSITIONS AND MAX WINDS
INITIAL 10/2100Z 20.5N 60.0W 70 KTS
12HR VT 11/0600Z 21.5N 61.2W 80 KTS
24HR VT 11/1800Z 22.5N 62.8W 85 KTS
36HR VT 12/0600Z 23.4N 64.7W 90 KTS
48HR VT 12/1800Z 24.0N 67.0W 95 KTS
72HR VT 13/1800Z 25.0N 71.5W 105 KTS
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